Vacuum cleaner and device having ion generator

ABSTRACT

When the electrically driven fan ( 14 ) of a vacuum cleaner is driven, air containing dust is drawn into the cleaner main body ( 1 ) through a hose ( 7 ) connected to a hose socket ( 8 ) and is exhausted into the outside of the cleaner main body ( 1 ) through an exhaust port ( 1   b ) via first and second suction passageways ( 10, 13 ). Disposed outside the first suction passageway ( 10 ) is an ion generator ( 23 ), it being arranged that plus and minus ions generated in the ion generator ( 23 ) are fed to the air stream flowing in the first suction passageway ( 10 ). Since the plus and minus ions kill floating germs in the air stream, the exhaust can be purified.

TECHNICAL FIELD

The present invention relates to an electric vacuum cleaner, and moreparticularly to an electric vacuum cleaner provided with a sterilizingfunction.

BACKGROUND ART

As a conventional electric vacuum cleaner provided with an ozonegenerating function, the one disclosed in Japanese Patent ApplicationLaid-Open No. H1-238815 will be described below with reference to FIG.30. In this conventional electric vacuum cleaner, inside a body 101thereof is formed a suction air passage 104 that runs from a hose socket102 formed in the front wall of the body 101 to an exhaust opening 103formed in the rear wall of the body 101, and in this suction air passage104 are arranged a dust collection bag 105, a dust filter 106, and anelectric blower 107 in this order. The dust collection bag 105 permitsair to pass therethrough. The electric blower 107 communicates with theexhaust opening 103.

When the electric blower 107 is driven, air containing dust is sucked inthrough a suction hose 108 fitted into the hose socket 102, is thenpassed through the dust collection bag 105, dust filter 106, andelectric blower 107, and is then discharged out of the body 101 throughthe exhaust opening 103. Meanwhile, the dust collection bag 105 removesthe dust contained in the air.

On the other hand, inside the body 101 of this electric vacuum cleaner,outside and above the suction air passage 104 is formed an ozonereservoir 109, in which an ozone generator 110 is provided. While theelectric blower 107 is operating, ozone generated by the ozone generator110 is reserved in the ozone reservoir 109, and, when the electricblower 107 is de-energized, valves 111 and 112 are opened so that thereserved ozone is fed into the suction air passage 104 so as to killgerms present in the suction air passage 104.

In this conventional electric vacuum cleaner, the ozone fed into thesuction air passage 104 acts on the stream of air that has been cleanedby the dust collection bag 105, but does not sufficiently act on thedust and germs collected in the dust collection bag 105. This makes itimpossible for ozone to exert a satisfactory antibacterial effect.

Moreover, since ozone is reserved in the ozone reservoir 109 duringoperation, the body 101, which is formed of synthetic resin, is exposedto the reserved ozone for a long time. This causes the body 101 todeteriorate, making it prone to cracks and breakage in the relevant partthereof In particular, in a vacuum-type cleaner, cracks are likely todevelop in a part thereof where the pressure is low during operation,lowering the suction performance and leading ultimately to a burst.

DISCLOSURE OF THE INVENTION

The present invention has been devised to address the aforementionedproblems with conventional electric vacuum cleaners. Specifically,according to the present invention, an electric vacuum cleaner that,while driving an electric blower, sucks in air containing dust such asdirt, particulate dust, and water, then passes the air through a suctionair passage, and then discharges the air out of itself is provided withan ion generator. The ion generator generates H⁺(H₂O)_(n) as positiveions and O₂ ⁻(H₂O)_(m) as negative ions, which are fed into the suctionair passage. In this construction, the positive and negative ionsgenerated by the ion generator are discharged into the suction airpassage so as to sterilize the stream of air, exerting a satisfactoryantibacterial effect. The ion generator may be disposed outside thesuction air passage, with the ions fed into the suction air passage. Thepositive and negative ions generated by the ion generator may be fedinto the air on the downstream side of the electric blower where the airis about to be discharged.

Incidentally, as the ion generator generates positive and negative ions,it also generates ozone as a byproduct. Accordingly, by treating thepart of the suction air passage around the needle-shaped electrode withanti-ozone treatment, it is possible to prevent its deterioration causedby ozone. As is well known, as temperature rises, ozone exertsincreasingly high oxidizing power, prompting the deterioration of thecomponents arranged nearby, especially those formed of resin materials.For this reason, to reduce the oxidizing power of the ozone presentaround the electrode, i.e., the source at which ozone is generated, itis ideal to place the ion generator away from a heat source such as theelectric blower.

By passing the air sucked into the electric vacuum cleaner through anpurification filter before discharging it out of the electric vacuumcleaner, and by mixing the air that has been passed through thepurification filter with the positive and negative ions, it is possibleto kill germs that have passed through the purification filter withoutbeing caught by it.

Alternatively, according to the present invention, an electric vacuumcleaner that has casters arranged on both side faces of a body having anelectric blower housed therein and that exhausts the electric blower ofair through ventilation openings formed in the casters is provided withan ion generator that generates H⁺(H₂O)_(n) as positive ions and O₂⁻(H₂O)_(m) as negative ions into a mixing chamber formed by the casters.In this construction, positive and negative ions are generated by theion generator inside the mixing chamber formed by the casters, and thepositive and negative ions are then discharged, by being carried by thestream of air passing through the electric vacuum cleaner, through theventilation openings formed in the casters to sterilize the interior ofthe room. This is expected to produce a satisfactory antibacterialeffect.

Alternatively, an electric vacuum cleaner has an electric blower and anion generator housed in a body, and the body is provided with,independently of a control panel for controlling the electric vacuumcleaner, a drive switch for driving the ion generator. With thisconstruction, for example, when only the body of the electric vacuumcleaner, i.e., with its hose removed, is placed inside a closet or thelike, and the drive switch is turned on to suck in and discharge the airinside the space such as a closet, it is possible to discharge thegenerated positive and negative ions into the space and thereby achievepurification in the space.

In this case, it is preferable to provide timer means for driving theelectric blower and the ion generator for a predetermined length of timeafter the drive switch is operated.

The quantities of ions generated by the ion generator may be controlledaccording to the power with which the electric blower is driven. Thisprevents unnecessary operation of the ion generator, and thus helpsextend its life. Moreover, it is possible to prevent unnecessarydischarge of ions.

The ion generator may be driven for a predetermined length of timeaccording to the storage state of the electric vacuum cleaner. Thispermits purification to be performed automatically for a predeterminedlength of time inside a comparatively airtight space such as the storagespace during storage.

If both positive and negative ions are generated with a single iongenerating electrode, part of them cancel each other, resulting in lowereffective quantities of ions generated at the initial stage ofgeneration. To avoid this, it is preferable to provide two electrodes sothat positive and negative ions are generated from separate electrodes.

This makes it possible to variably control the proportion between thequantities of positive and negative ions generated.

Incidentally, the aforementioned ion generator is of the type thatgenerates both positive and negative ions or negative ions alone. It isbelieved that positive and negative ions exert an effect of killinggerms floating in the air, and that negative ions exert an effect ofrelaxing the feelings of humans.

It is particularly preferable to design and operate the ion generator insuch a way that, when air is fed to the ion generating part thereof atthe rate of 50 cm/s or more, the concentrations of positive and negativeions are each 10,000 ions/cm³ or more at a position 10 cm away from theion generating part. This helps obtain a high sterilizing effect.

Here, only such examples are dealt with in which an electric vacuumcleaner is provided with an ion generator. It is, however, also possibleto provide an ion generator for generating ions in any device that isfurnished with an air blowing means and a moving means, such as wheels,so that it can be moved around while in use, for example a mobilecleaning robot. This permits the ion generator to be moved around whilein operation, and thus makes it possible to purify air efficiently andunattendedly over a wide area or behind an obstacle where a stationaryion generator cannot reach. Thus, it is possible to purify air whereversuch a device can be brought into without performing cleaning bysuction.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an external side view showing the electric vacuum cleaner of afirst embodiment of the invention.

FIG. 2 is a side sectional view showing the internal construction of thebody of the electric vacuum cleaner.

FIG. 3 is an enlarged side sectional view showing the internalconstruction of the ion generator used in the electric vacuum cleaner.

FIG. 4 is an enlarged view of another example of the needle-shapedelectrode of the ion generator.

FIG. 5 is an enlarged view of still another example of the needle-shapedelectrode of the ion generator.

FIG. 6 is a sie sectional view showing the internal construction of theelectric vacuum cleaner of a second embodiment of the invention.

FIG. 7 is a side sectional view showing the internal construction of thebody of the electric vacuum cleaner of a third embodiment of theinvention.

FIG. 8 is a side sectional view showing the internal construction of thebody of the electric vacuum cleaner of a fourth embodiment of theinvention.

FIG. 9 is an external perspective view of the ion generator used in theelectric vacuum cleaner, as seen from the ion generating element side.

FIG. 10 is an external perspective view of the ion generator, as seenfrom the side opposite to the ion generating element.

FIG. 11 is an exploded perspective view of the ion generator.

FIG. 12A is an outline perspective view showing the ion generatingelement of the ion generator.

FIG. 12B is a sectional view showing the ion generating element of theion generator.

FIG. 13 is an enlarged side sectional view sowing another example of theinfernal construction of the ion generator.

FIG. 14 is a side sectional view around the exhaust opening, showing theinternal construction of the body of another embodiment of the electricvacuum cleaner.

FIG. 15 is a side sectional view showing the internal construction ofthe body of the electric vacuum cleaner of a fifth embodiment of theinvention.

FIG. 16 is a side sectional view around the exhaust opening, showing theinternal construction of the body of another embodiment of the electricvacuum cleaner.

FIG. 17 is a side sectional view showing the internal construction ofthe body of the electric vacuum cleaner of a sixth embodiment of theinvention.

FIG. 18 is a vertical sectional view showing the internal constructionof the body, in its rear part, of the electric vacuum cleaner of a sixthembodiment of the invention.

FIG. 19 is a sectional view taken along line A-A shown in FIG. 18.

FIG. 20A is a side view showing the posture of the body of the electricvacuum cleaner during cleaning operation.

FIG. 20B is a side view showing the posture of the body of the electricvacuum cleaner during storage.

FIG. 21 is a sectional view taken along line A-A shown in FIG. 18,showing another example of the electric vacuum cleaner.

FIG. 22 is a vertical sectional view showing the internal constructionof the body, in its rear part, of still another example of the electricvacuum cleaner.

FIG. 23 is an external perspective view showing the electric vacuumcleaner of an eighth embodiment of the invention.

FIG. 24 is a side sectional view showing the internal construction ofthe body of the electric vacuum cleaner.

FIG. 25 is a side sectional view showing the internal construction ofthe body of the electric vacuum cleaner of a ninth embodiment of theinvention.

FIG. 26 is a diagram showing the measurements of the concentrations ofions generated by the electric vacuum cleaner.

FIG. 27 is a diagram showing the effect of eliminating ammonia achievedby the operation of the electric vacuum cleaner.

FIG. 28 is a side sectional view showing the internal construction ofthe body of an example of an exhaust-recycling-type electric vacuumcleaner provided with an ion generator.

FIG. 29A is a circuit diagram of the control circuit for controlling theelectric blower and ion generator in an electric vacuum cleaneraccording to the invention, showing an example of the control circuitthat drives the electric blower and ion generator simultaneously.

FIG. 29B is a circuit diagram of the control circuit for controlling theelectric blower and ion generator in an electric vacuum cleaneraccording to the invention, showing an example of the control circuitused when the ion generator shown in FIG. 13 is provided in the body.

FIG. 30 is an external side sectional view of a conventional electricvacuum cleaner.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described indetail with reference to the drawings. The examples describedhereinafter all deal with a so-called cyclone-type electric vacuumcleaner, in which air containing dust and the like is sucked into acylindrical dust collection case and is passed through a circularsuction air passage in such a way that the air swirls around inside thecylinder of the dust collection case so that, by the action ofcentrifugal force, the dust and the like contained in the air isseparated therefrom and collected.

A first embodiment of the invention will be described below withreference to the drawings. FIG. 1 is an external view showing theoutward appearance of the cyclone-type electric vacuum cleaner of afirst embodiment of the invention, and FIG. 2 is a side sectional viewof its body. As will be clear from these figures, the electric vacuumcleaner is roughly divided into the following parts: an electric vacuumcleaner body (hereinafter, simply the “body”) 1; a dust collector 2 thatis removably attached to the body 1; a connection pipe 3 that has acontrol panel 4 and a handle 5 provided at the upper end thereof andthat has a nozzle unit 6 removably attached to the lower end thereof;and a connection hose 7 of which one end is removably connected to theconnection pipe 3 and of which the other end is removably fitted into ahose socket 8 formed as an air intake opening in the body 1.

As shown in FIG. 2, the body 1 is built as a casing of which the contouras seen from the side is substantially L-shaped so as to form, in acentral part in the top face thereof, a housing 9 for removablysupporting the dust collector 2. Inside the body 1 are provided thefollowing parts: a first suction air passage 10 that starts from thehose socket 8, which is formed in the front wall of the body 1, thenextends horizontally inside the body 1, then bends upward, and thenconnects to a first coupling member 11 provided on a horizontal wallsurface 9 a of the housing 9; a second suction air passage 13 that is,at one end thereof, connected to a second coupling member 12 provided onthe horizontal wall surface 9 a at a level higher than the firstcoupling member 11 and that then bends downward so that the other endthereof extends toward an exhaust opening 1 b formed in the rear wall ofthe body 1; an electric blower 14 that is connected to the other end ofthe second suction air passage 13; and a deodorizing filter 15 that isdisposed between the electric blower 14 and the exhaust opening 1 b.

As shown in FIG. 2, the dust collector 2 is composed of the followingparts: a dust cup 16 built as a cylindrical container that is open atthe top and that has an inflow pipe 20 fitted into the side wallthereof; a lid 17 that is fitted on the dust cup 16 so as to close thetop opening thereof; an exhaust cylinder 18 that is fitted in a centralpart of a separator plate 17 a provided in the lid 17 so as to suspendtherefrom into the dust cup 16; and an exhaust pipe 19 that is housedinside the lid 17 and that is connected, at one end thereof, to anexhaust port 18 a of the exhaust cylinder 18 and, at the other endthereof, to an outflow pipe 21 fitted into the side wall of the lid 17.

A filter 18 b is arranged in the outer circumferential wall of theexhaust cylinder 18. The dust collector 2 is removably housed in thehousing 9 of the body 1, and, when it is housed in position, the inflowpipe 20 and outflow pipe 21 communicate with the first coupling member11 and second coupling member 12, respectively. Here, the first couplingmember 11 and second coupling member 12 are both formed of elasticmaterial such as rubber so that, in particular by flange-like partsformed at one end thereof, their communication with the inflow pipe 20and outflow pipe 21 is kept air-tight when the dust collector 2 ishoused in the housing 9.

A handle 22 is fitted on the top surface of the lid 17 of the dustcollector 2. An ion generator 23 is disposed near the hose socket 8, onthe inner surface side of the top wall of the body 1. The ion generator23 discharges ions from an electrode by applying a voltage to theelectrode. Here, by switching the type (negative or positive) of thevoltage with which the electrode is loaded, it is possible to switch thegenerated and thus discharged ions between positive and negative ions.

By providing a selecting means for switching, continuously or atpredetermined time intervals, the type of the voltage with which theelectrode is loaded, it is possible to easily choose between positiveand negative ions. Negative ions exert a healing effect, and dischargingpositive and negative ions simultaneously produces a sterilizing effect.The ion generator 23 may be configured in any manner, so long as it isdesigned as a device provided with a means for generating ions. In thefollowing descriptions, the healing, sterilizing, and other effectsbrought about by ions are collectively referred to as “purification.”

Now, the ion generator 23 will be described, assuming that it has aneedle-shaped electrode. A practical example of the details of the iongenerator 23 is shown in FIG. 3. As shown in this figure, the iongenerator 23 has a body casing 24, which has an ion outflow port 25formed in the bottom face thereof and of which the interior is dividedinto a front chamber 27, a rear chamber 28, and an upper chamber 29. Thefront chamber 27 is located in front of the rear chamber 28, with thetwo chambers separated from each other by a separation wall 26. Theupper chamber 29 is located above the front and rear chamber 27 and 28,and communicates only with the rear chamber 28 through a communicationport 26 a.

In the front chamber 27 is arranged an ion generating circuit 30. On theother hand, in the rear chamber 28, which serves as an ion generationchamber, is arranged a needle-shaped electrode 31, which has its tip endshaped into a needle pointing toward the ion outflow port 25 and whichserves as an ion generating element. A conductor lead 32, which isformed of a single wire, runs from the ion generating circuit 30, thenpenetrates the separation wall 26, and then further runs inside the rearchamber 28, where the conductor lead 32 is supported by a supportingmember 33 formed of insulating material such as synthetic resin andprovided on the wall. Below the supporting member 33, the conductor lead32 connects, both electrically and mechanically, to the needle-shapedelectrode 31, with the needle-shaped end thereof pointing downward.

Thus, supported by the supporting member 33 at its top, theneedle-shaped electrode 31 is stably kept in position. In a case wherethe conductor lead 32 is formed of twisted wires, the needle-shapedelectrode 31 may be supported directly by the supporting member 33. Afilter 34 is arranged in the upper chamber 29.

The ion generator 23 configured as described above is disposed near thehose socket 8, on the inner surface side of the top wall of the body 1,with the ion outflow port 25 connected to a connection port 10 a formedin the middle of the first suction air passage 10. The filter 34arranged inside the upper chamber 29 faces a number of air intake holes36 formed in the top wall of the body 1. More precisely, these airintake holes 36 are formed all over a reversed-dish-shaped cover 35 thatcloses an opening la formed in the top wall of the body 1 and therebycovers the filter 34 arranged in the upper chamber 29.

In FIG. 2, the deodorizing filter 15 located on the downwind side of theneedle-shaped electrode 31 is composed of a corrugated-honeycomb-shapedmember coated with a low-temperature deodorant catalyst and anabsorbent. This deodorizing filter 15 is removably disposed between theelectric blower 14 and the exhaust opening 1 b so that it can bereplaced and cleaned to keep the interior of the electric vacuum cleanerclean. The deodorizing filter 15 may be composed of a filter or a pieceof unwoven fabric impregnated with a low-temperature deodorant catalystand an absorbent, but a honeycomb-shaped structure is preferable becauseit minimizes the pressure loss. The deodorizing filter 15 may be treatedwith antibacterial treatment.

The low-temperature deodorant catalyst is a copper-manganese-based oxidethat oxidizes and thereby decomposes order-producing substances such asamine- and thiol-based volatlie substances and hydrogen sulfide. Acopper-manganese-based oxide also funstions as an ozone-decomposingcatalyst, and thus helps decompose ozone. This eliminats the need toseparately provide an ozone eliminating device, and thus helps minimizethe increse in the manufacturing costs of the electric vacuum cleaner.Moreover, it is possible to reduce the ozone concentration to so low alevel as to be negligible in terms of the deteriorztion of resin-moldedcomponents.

Thus, the ozone contained in the air sucked in is decomposed by thedeodorizing filter 15 provided in the body 1, and is therefore notdischarged out of the body 1. The deodorizing filter 15 may beimpregnated with a dedicated ozone-decomposing catalyst that effectivelydecomposes ozone. Examples of such ozone-decomposing catalysts include,to name a few, manganese dioxide, platinum powder, lead dioxide, copperoxide II, and nickel.

The deodorizing filter 15 may be provided with a HEPA filter or asterilizing filter impregnated with a germicide. This helps furtherenhance the sterilizing, antibacterial, and dust-removing effects. Thedeodorizing filter 15 may be impregnated with an absorbent. Thisabsorbent is for absorbing odor-producing substances, ozone, andairborne germs. Examples of such absorbents include, to name a few,silica gel, activated charcoal, zeolite, and sepiolite. The deodorizingfilter 15 may be separately provided with a granulate or particulateabsorbent.

The electric vacuum cleaner according to the invention is constructed asdescribed above, and operates as described below. When the control panel4 is so operated as to start operation, the electric blower 14 and theion generating circuit 30 are energized, so that the electric blower 14starts to be driven to suck air in through the nozzle unit 6 and the iongenerating circuit 30 starts to operate to apply a high voltage to theneedle-shaped electrode 31. As a result, first, as the electric blower14 is driven, as indicated by broken-line arrows in FIG. 1, the air,containing dust, sucked in through the nozzle unit 6 is introduced,through the connection pipe 3, connection hose 7, and hose socket 8,into the body 1.

As air is sucked in in this way, inside the body 1, as indicated bybroken-line arrows in FIG. 1, the stream of air passing through thefirst suction air passage 10 produces a negative pressure near theconnection port 10 a and the ion outflow port 25, and thus the air inthe rear chamber 28, which serves as the ion generation chamber of theion generator 23, is sucked into the first suction air passage 10. As aresult, air is sucked in through the air intake holes 36 from outside,is then passed through the filter 34, and is then, along with the ionsgenerated in the rear chamber 28, sucked into the first suction airpassage 10.

A blower (for example, like the blower 23 a shown in FIG. 13) may beadditionally provided to blow out the generated ions through the ionoutflow port 25 of the ion generator 23. This permits ions to be fedeffectively into the first suction air passage 10. Moreover, ions canthen be discharged irrespective of whether the electric blower 14 isbeing driven or not. This makes it possible to discharge ions to purifyair even when the electric blower 14 is not operating.

This air containing ions is, along with the stream of air sucked throughthe hose socket 8 into the first suction air passage 10, sucked throughthe first coupling member 11 and the inflow pipe 20 into the dust cup 16while swirling around. Thus, the stream of air swirls around inside thedust cup 16, with the result that, by the action of centrifugal force,the dust contained in the stream of air is separated from the air and iscollected inside the dust cup 16.

On the other hand, the air having dust removed therefrom and thuspurified is sucked through the filter 18 b into the exhaust cylinder 18,is then passed through the exhaust pipe 19, outflow pipe 21, and secondcoupling member 12 into the second suction air passage 13, and is thenpassed through the electric blower 14 and deodorizing filter 15 so as tobe discharged out of the body 1 through the exhaust opening 1 b.Meanwhile, various germs present in the stream of air are killed by theions generated by the needle-shaped electrode 31, with the result thatthe air is purified.

The present invention works as described above, and the ion generator 23mentioned above works as described below. When a high voltage is appliedfrom the ion generating circuit 30 by way of the conductor lead 32 tothe needle-shaped electrode 31, an electric field concentrates on thepoint of the needle-shaped electrode 31. Thus, when the air taken inthrough the air intake holes 36 reaches around the needle-shapedelectrode 31, insulation in the air is destroyed locally at the point ofthe needle-shaped electrode 31, causing corona discharge.

The corona discharge here produces positive and negative ions, whichflock together and surround airborne germs floating in the air and killthem by the action of active species such as hydroxyl radical —OH andhydrogen peroxide H₂O₂. Thereafter, the deodorizing filter 15 absorbsand thereby eliminates the odor-producing substances originating fromthe dust and the like collected in the dust cup 16 and elsewhere and theminute quantity of ozone produced by the corona discharge. When themotor 54 of the electric blower 14 is not operating, positive andnegative ions may be fed directly to the dust cup 16 to fill it with theions so as to enhance the sterilizing effect inside the dust cup 16.

In this embodiment, the conductor lead 32 is given a length of 200 mm orless to reduce the lowering of discharge efficiency and to permit easywiring. Preferably, the conductor lead 32 is given a length of 100 mm orless to further reduce the lowering of discharge efficiency; morepreferably, it is given a length of 50 mm or less to permit connectionof the needle-shaped electrode 31 with almost no lowering of dischargeefficiency.

As the result of the corona discharge at the needle-shaped electrode 31,when the voltage applied thereto is positive, positive ions, mainlyH⁺(H₂O)_(n), are generated; when the voltage is negative, negative ions,mainly O₂ ⁻(H₂O)_(m), are generated. These positive and negative ions,namely H⁺(H₂O)_(n) and O₂ ⁻(H₂O)_(m), flock together on the surface ofmicroorganisms, and surround airborne germs such as microorganismspresent in the air.

Then, as expressed by the formulae noted below, they collide together toproduce active species, namely hydroxyl radical —OH and hydrogenperoxide H₂O₂, on the surface of microorganisms and the like and therebykill airborne germs. In this way, in this embodiment, airborne germspresent in the air are killed by the action of positive and negativeions. This makes it possible to obtain a more efficient sterilizingeffect than with conventional methods of sterilization exploiting theaction of ozone.H⁺(H₂O)_(n)+O₂ ⁻(H₂O)_(m)→—OH+1/2O₂+(n+m)H₂O  (1)

Moreover, there is provided no opposing electrode opposite theneedle-shaped electrode 31, or no collecting electrode for collectingpositive ions. Thus, no ions are absorbed by such electrodes due to avoltage difference. This permits ions to be spread widely inside therear chamber 28, i.e., the ion generation chamber, even without a strongblow of air. Accordingly, the ions spread in the rear chamber 28 arethen efficiently sucked through the connection port 10 a and the ionoutflow port 25 into the first suction air passage 10. This helpsenhance the sterilizing power.

Moreover, both a positive and a negative voltage are applied to theneedle-shaped electrode 31, and therefore the ion generating circuit 30never remains charged even without being grounded. This eliminates theneed to secure a ground to the earth, and thus permits the electricvacuum cleaner to be moved freely around.

According to formulae (1) to (3) noted above, to produce the activespecies, the quantity of negative ions generated needs to be equal to orlarger than the quantity of positive ions generated. In this embodiment,the quantity of positive ions generated is made smaller than that ofnegative ions. This permits positive and negative ions to flock togetheron the surface of microorganism and produce active species to killairborne germs, and simultaneously permits the extra negative ions tosuppress the proliferation of airborne germs.

Here, if the quantity of positive ions generated is less than 3% of thequantity of negative ions generated, —OH is produced in too small aquantity to obtain satisfactory sterilizing power. For this reason, inthis embodiment, where sterilization is aimed at, the quantity ofpositive ions generated is made 3% or more of the quantity of negativeions generated. Moreover, by making the quantity of positive ionsgenerated equal to or more than 5,000 ions (preferably, 10,000 ions) per1 cm³, it is possible to obtain sufficient sterilizing power. Moreover,by providing control that permits the proportions of positive andnegative ions generated to be varied, it is possible to generateappropriate quantities of positive and negative ions according towhether the desired effect is a sterilizing, healing, or other effect.

Two ways of controlling the quantities of ions generated are:

(1) to vary the durations for which a positive and a negative voltageare applied respectively; and

(2) to control the duty of voltage application, i.e., the durations forwhich a voltage is and is not applied.

Moreover, the voltage applied to the needle-shaped electrode 31 is madeso low as to minimize the quantity of ozone produced by coronadischarge. In addition, when the duty is controlled, it is preferable toturn on and off the applied voltage repeatedly at short time intervals,because this helps reduce the generation of ozone. As temperature rises,ozone exerts increasingly high oxidizing power, prompting thedeterioration of the components arranged nearby, especially those formedof resin materials.

To cope with this problem, in this embodiment, the needle-shapedelectrode 31 is disposed in an upstream part of the stream of air so asnot to be affected by the heat generated by the electric blower 14,i.e., inside the rear chamber 28, which is located away from a heatsource such as the electric blower 14. As a result, even when ozone isgenerated, its oxidizing power around the needle-shaped electrode 31,i.e., the source at which it is generated, is minimized. As shown inFIG. 4, the needle-shaped electrode 31 may be composed of a plurality ofneedle-shaped conductors 31 a that are kept at an equal potential andthat are supported by a common supporting member 33 via conductor leads32 a.

Alternatively, as shown in FIG. 5, a plurality of needle-shaped parts 31b, for example three of them, may be formed at the lower end of a singleneedle-shaped electrode 31. In this case, ions are discharged from theends of the needle-shaped parts 31 b into a range of angles coveringabout 45°. In this way, by arranging a plurality of needle-shaped parts31 b so that they point in different directions, it is possible todischarge ions into a wide range and thereby obtain enhanced purifyingpower.

The direction in which the needle-shaped electrode 31 causes dischargeis set to be along the direction of the stream of air. This permits ionsto be discharged over a wider area in the direction of the stream ofair. This also makes dust less likely to settle on the needle-shapedelectrode 31, permitting easy maintenance.

Part of the wall of the suction air passage, especially the part thereoflocated on the downstream side of the ion generator 23, may be treatedwith anti-ozone treatment as by being coated with a metal, or beingcoated with an ozone-resistant substance, or being covered with a metalsheet. This helps confine most of the generated ozone inside the wall ofthe suction air passage, and thus helps alleviate the deterioration ofthe components arranged nearby other than the wall of the suction airpassage.

If the distance (L in FIG. 3) between the supporting member 33 and theneedle-shaped electrode 31 is too short, when the humidity in the roomwhere cleaning is performed is high, a high voltage may be applied tothe supporting member 33. To avoid this, the distance L is set to be 3.5mm or more, for example 5 mm, so that the supporting member 33 islocated away from the needle-shaped electrode 31 and is thereby surelyinsulated therefrom. This permits the high voltage to be stably appliedto the needle-shaped electrode 31, permits corona discharge to takeplace surely, and thus permits ions to be discharged stably.

When both positive and negative ions are generated with a singleneedle-shaped electrode 31, part of them cancel each other, resulting inlower effective quantities of ions generated at the initial stage ofgeneration. This problem can be overcome by providing two electrodes sothat positive and negative ions are generated separately. This helpsincrease the effective quantities of ions generated.

Moreover, this construction permits the two electrodes to be controlledindependently, and thus permits easy and separate adjustment of thequantities of positive and negative ions. Needles to say, even when twoelectrodes are provided in this way, it is possible to drive only one ofthem to generate ions of one type alone.

As the circuit configuration, applied voltage, electrode shape,electrode material, and other factors are varied, the two electrodes,for example a plurality of electrodes consisting of two types ofelectrodes, permit easy adjustment of the balance with which ions aregenerated. Moreover, by arranging the two electrodes 10 mm or more, forexample 30 mm, apart from each other, it is possible to use thegenerated ions effectively for sterilization with almost no cancellationbetween positive and negative ions.

The two electrodes may be given any other shape than a needle-like one.For example, ions may be generated with a voltage applied betweenelectrodes that are arranged so as to face each other with an insulatorsandwiched in between. By arranging a plurality of electrodes atpredetermined intervals (for example, 10 mm) in a directionapproximately perpendicular to the direction of the stream of air, andarranging the electrodes, especially when there are provided three ormore of them, in such a way that they are inclined alternately inopposite directions, and arranging every two adjacent electrodes, whichare inclined in opposite directions, at predetermined angles such thattheir points tend to overlap, i.e., make contact with, each other in thedirection of the stream of air (for example, at angles of about 30° insuch directions in which they come closer together toward the stream ofair). This permits ions to be generated and distributed more evenly overa wider area, and thus helps further enhance the sterilizing power.

In this case also, as described above, by generating positive andnegative ions alternately, or by generating positive and negative ionswith separate electrodes, it is possible to efficiently and evenlygenerate and distribute ions over a wide area, and thereby furtherenhance the sterilizing power.

The ion generator 23 is driven with one of the following patterns oftiming:

(1) The ion generator 23 is turned on and off completely in synchronismwith the timing with which the power switch of the electric blower 14 isturned on and off. This permits the ion generator 23 to be turned on andoff as the user wishes it to be, and thus contributes to safety.

(2) The ion generator 23 is turned off with a delay after the powerswitch of the electric blower 14 is turned off. This permitssterilization of the air that has just been exhausted and is stillfloating around.

(3) The ion generator 23 is turned on and off independently of theturning on and off of the power switch of the electric blower 14. Thispermits the ion generator 23 to be turned on to purify air even duringstorage, and thus makes it possible to purify the air inside the storagespace, for example a closet, during storage.

(4) The quantities of ions generated are controlled in a mannerinterlocked with the control of the power with which the electric blower14 is driven. This prevents unnecessary operation of the ion generator23, and thus helps extend its life. Moreover, it is possible to preventunnecessary discharge of ions.

A second embodiment of the invention will be described below withreference to the drawings. FIG. 6 is a diagram showing the secondembodiment of the invention. In this embodiment, an ion generator 23 iscoupled to the inner wall surface of the ceiling of the lid of the dustcollector 2. The ion outflow port 25 formed in the bottom face of thebody casing 24 communicates with an opening 17 b formed in the separatorplate 17 of the lid 17, and outside air is taken in through air intakeholes 36 formed in the ceiling wall of the lid 17.

In this construction, when the control panel 4 is so operated as tostart operation, the electric blower 14 and the ion generating circuit30 are energized, so that the electric blower 14 starts to be driven tosuck air in through the nozzle unit 6 and the ion generating circuit 30starts to operate to apply a high voltage to the needle-shaped electrode31.

As a result, first, as the electric blower 14 is driven, the air,containing dust, sucked in through the nozzle unit 6 is introduced,through the hose socket 8, into the body 1. As air is sucked in in thisway, inside the body 1, as indicated by broken-line arrows in FIG. 6,the air sucked into the suction air passage 10 is sucked through theinflow pipe 20 into the dust cup 16 of the dust collector 2 whileswirling around.

Thus, the stream of air swirls around inside the dust cup 16, with theresult that, by the action of centrifugal force, the dust contained inthe stream of air is separated from the air and is collected inside thedust cup 16. The air having dust removed therefrom and thus purified issucked through the filter 18 b into the exhaust cylinder 18, is thenpassed through the exhaust pipe 19, outflow pipe 21, and second couplingmember 12 into the second suction air passage 13, and is then passedthrough the electric blower 14 and deodorizing filter 15 so as to bedischarged out of the body 1 through the exhaust opening 1 b.

On the other hand, as indicated by broken-like arrows in FIG. 6, the airswirling around inside the dust cup 16 produces a negative pressure nearthe ion outflow port 25, and thus the air in the rear chamber 28 issucked into the dust cup 16. As a result, the air sucked in through theair intake holes 36 from outside is passed through the filter 34, isthen, along with the ions generated in the rear chamber 28, sucked intothe dust cup 16, is then, along with the stream of air swirling insidethe dust cup 16, into the second suction air passage 13, and is thenpassed through the electric blower 14 and the deodorizing filter 15 soas to be discharged out of the body 1 through the dust cup 16.Meanwhile, various germs present in the stream of air are killed by theions generated by the needle-shaped electrode 31, with the result thatthe air is purified.

In this embodiment, as described above, the ion generator 23 is disposedinside the dust collector 2 and outside the suction air passage, and theions generated by the ion generator 23 are discharged evenly over theentire upper region of the interior of the dust cup 16. This permitseffective killing of airborne germs captured inside the dust cup 16 overthe entire region thereof.

A third embodiment of the invention will be described below withreference to the drawings. FIG. 7 is a diagram showing the thirdembodiment of the invention. In this embodiment, an ion generator 23 isdisposed along the second suction air passage 13. Specifically, the bodycasing 24 of the ion generator 23 is disposed along the second suctionair passage 13. The ion outflow port 25 formed in the bottom face of thebody casing 24 communicates with the second suction air passage 13, andoutside air is taken in through air intake holes 36 formed in an upperpart of the side wall of the body 1.

In this construction, when the control panel 4 is so operated as tostart operation, the electric blower 14 and the ion generating circuit30 are energized, so that the electric blower 14 starts to be driven tosuck air in through the nozzle unit 6 and the ion generating circuit 30starts to operate to apply a high voltage to the needle-shaped electrode31.

As a result, first, as the electric blower 14 is driven, the air,containing dust, sucked in through the nozzle unit 6 is introduced,through the hose socket 8, into the body 1. As air is sucked in in thisway, inside the body 1, as shown in FIG. 7, the air sucked into thefirst suction air passage 10 is sucked through the inflow pipe 20 intothe dust cup 16 while swirling around.

Thus, the stream of air swirls around inside the dust cup 16, with theresult that, by the action of centrifugal force, the dust contained inthe stream of air is separated from the air and is collected inside thedust cup 16. The air having dust removed therefrom and thus purified issucked through the filter 18 b into the exhaust cylinder 18, is thenpassed through the exhaust pipe 19, outflow pipe 21, and second couplingmember 12 into the second suction air passage 13, and is then passedthrough the electric blower 14 and deodorizing filter 15 so as to bedischarged out of the body 1 through the exhaust opening 1 b.

On the other hand, the stream of air passing through the second suctionair passage 13 produces a negative pressure near the ion outflow port25, and thus the air in the rear chamber 28 is sucked into the secondsuction air passage 13. As a result, air is sucked in through the airintake holes 36 from outside, is then passed through the filter 34, andis then, along with the ions generated in the rear chamber 28, passedthrough the second suction air passage 13 to the electric blower 14.

Thereafter, the air is passed through the deodorizing filter 15 so as tobe discharged out of the body 1 through the exhaust opening 1 b.Meanwhile, various germs present in the stream of air are killed by theions generated by the needle-shaped electrode 31, with the result thatthe air is purified. The present invention is applicable not only tocyclone-type electric vacuum cleaners but also to electric vacuumcleaners of any other types.

A fourth embodiment of the invention will be described below withreference to the drawings. The first to third embodiments describedabove deal with an ion generator 231 having a needle-shaped electrode.The ion generator 231 is simply for discharging ions from an electrodeas a result of application of a voltage thereto, and thus can beconstructed in various manners. The fourth to seventh embodimentsdescribed below deal with a grid-shaped ion generator 231 that isconstructed differently from the ion generator 23 having a needle-shapedelectrode as shown in FIG. 3.

First, the construction of the ion generator 231 will be described. FIG.9 is an external perspective view of the ion generator 231 as seen fromthe ion generating element 210 side thereof, and FIG. 10 is an externalperspective view of the ion generator 231 as seen from the oppositeside. FIG. 11 is an exploded perspective view of the ion generator 231,FIG. 12A is an external perspective view of the ion generating element210, and FIG. 12B is a sectional view of the generating element 210.

The ion generating element 210 includes: a surface electrode 213 laid onthe surface of a flat-plate-shaped dielectric 211; a surface electrodecontact 215 formed on the surface of the dielectric 211 to permitelectric power to be fed to the surface electrode 213; an innerelectrode 212 buried inside the dielectric 211 and laid parallel to thesurface electrode 213; and an inner electrode contact 214 formed on thesurface of the dielectric 211 to permit electric power to be fed to theinner electrode 212. The dielectric 211 is composed of a top plate 211a, a bottom plate 211 b, and a surface protection plate 211 c.

The ion generator 231, which incorporates the ion generating element 210structured as described above, is provided with a voltage step-up coil251, a circuit board 252, a common case 253, and a lid plate 254. Thevoltage step-up coil 251 has a pair of high-voltage terminals and a pairof input terminals provided on one side of a resin case.

A circuit for generating a waveform for driving the ion generatingelement 210 is formed on one surface (the lower surface in FIG. 11) ofthe circuit board 252, and thus on this surface of the circuit board 252are mounted various circuit components, such as capacitors andsemiconductor devices. The circuit board 252 has four connection pinsfor external connection provided so as to protrude from the one surface.

The common case 253 is box-shaped. The common case 253 has a rectangularopening formed all over one side thereof to permit the circuit board 252to be inserted therein. On the opposite side thereof, the common case253 has a bottom part having a semicircular sectional shape. This bottompart is divided into a coil housing 253 b and a circuit componenthousing 253 c by a partition wall 253 a, which is formed substantiallyperpendicularly to the length direction and has a predetermined height.

All around the inside of the common case 253, at the same height as theupper edge of the partition wall 253 a, a support frame for supportingthe circuit board 252 is formed so as to protrude inward. At the rim ofthe open side of the common case 253, at two separate places on each ofthe opposite longer sides, depressions are formed with which the lidplate 254 engages.

The lid plate 254 is a flat plate formed of a resin material. In oneside of the lid plate 254 along its length, a rectangular depression isformed that corresponds to the ion generating element 210. In thisdepression is formed a hole 254 a, which has an elliptic window hole anda resistive element cavity integrally formed to penetrate the lid plate254 in positions corresponding to the surface electrode contact 214 andthe inner electrode contact 215 of the ion generating element 210.

When the ion generating element 210 is fitted into the aforementioneddepression of the lid plate 254 structured as described above, the lidplate 254 integrally holds the ion generating element 210.

To build the ion generator 231, the voltage step-up coil 251, circuitboard 252, common case 253, and the lid plate 254 having the iongenerating element 210 secured thereto, of which each is structured asdescribed above, are assembled together in the following manner.

First, the voltage step-up coil 251 is inserted, with the aforementionedhigh-voltage, ground, and input terminals protruding upward, into thecoil housing 253 b formed in the bottom part of the common case 253.Then, the coil housing 253 b is filled with a filling material 255 undera vacuum in such a manner as to prevent entry of bubbles. Thus, amolding for insulation is formed.

Thereafter, after the filling material 255 is dried and cured, thecircuit board 252 is inserted into the common case 253 through its topopening. The insertion here is performed in the following manner. First,the component-mounted side of the circuit board 252 is kept down, andthe connection holes for connection to the voltage step-up coil 251 arepositioned right above the voltage step-up coil 251 secured in the coilhousing 253 b. Then, the circuit board 252 is inserted until the bottomsurface thereof strikes the partition wall 253 c and the support frame.After the insertion, the aforementioned high-voltage, ground, and inputterminals are, at their one end, welded to their respective positions onthe top surface of the circuit board 252. As a result of this welding,the circuit board 252 is supported from below by the support frame andthe top edge of the partition wall 253 a, and is fixed in position, withthe high-voltage, ground, and input terminals serving as the supportlegs of the circuit board 252, by the voltage step-up coil 251, which inturn is fixed in position by the filling material 255.

After the circuit board 252 is fitted in this way, the lid plate 254,with the ion generating element 210 held therein as described above, isfitted. Here, the fitting is performed in the following manner. The hole254 a formed in one side of the lid plate 254 along its length ispositioned right above the window hole formed in the circuit board 252previously fixed in the common case 253, and then, while the surface ofthe lid plate 254 on which the ion generating element 210 is held iskept up, the lid plate 254 is fitted into the top opening of the commoncase 253. Here, the engagement claws formed on opposite edges of the lidplate 254 deform and then retrieve their original shapes to therebyengage with the corresponding depressions formed at the rim of theopening of the common case 253. Thus, the lid plate 254 is fitted at anappropriate distance from the top surface of the circuit board 252 insuch a way as to close the opening of the common case 253.

After the fitting, the filling material 255 is introduced through awindow hole 254 b formed in the lid plate 254 so that the fillingmaterial 255 fills the space between the lid plate 254 and the circuitboard 252. In this way, the space between the circuit board 252 and theion generating element 210 is filled with a molding for insulation. Whenthe filling material 255 is dried and cured, the assembly of the iongenerator 231 is complete.

The purpose of using a grid-shaped electrode as the surface electrode213 as shown in FIGS. 12A and 12B is to maximize the quantities of ionsgenerated when a drive voltage is applied thereto. On the other hand,the inner electrode 212 is formed as a strip-shaped electrode of whichthe center coincides with the center of the surface electrode 213 andwhich is smaller than the surface electrode 213 in both length andwidth. This shape also contributes to maximizing the quantities of ionsgenerated.

For example, a top plate 211 a and a bottom plate 211 b, each about 0.45mm thick, are laid together to form a dielectric 211 measuring about 15mm×37 mm×0.9 mm. On the surface of this dielectric 211, conductors, each0.25 mm wide, are arranged vertically and horizontally with a pitch of0.8 mm to form a grid-shaped surface electrode 213 measuring about 10.4mm×28 mm. Moreover, between the top plate 211 a and the bottom plate 211b, a sheet-shaped inner electrode 212 measuring about 6 mm×24 mm isformed. When, as a drive voltage, a high-voltage current having avoltage of about 4.6 kV (peak) and a frequency of 22 kHz was appliedbetween those electrodes, it was confirmed that the plasma dischargethat occurred between the electrodes 212 and 213 generated over 200,000ions/cc of positive ions and over 200,000 ions/cc of negative ions at aposition 25 cm away from the ion generating element 210. Thesequantities of ions generated are sufficient for air purification in atypically-sized room in a household.

The quantities of ions generated by the ion generator 231 can beincreased by making the ion generating element 210 larger, or by makingthe drive voltage higher. However, when the drive voltage is increased,the quantity of ozone generated increases accordingly. Thus, it is notpreferable to excessively increase the drive voltage, and it ispreferable, for example, to intermittently apply the drive voltage so asto reduce the quantity of ozone generated and simultaneously saveenergy.

In a case where the ion generator 231 constructed as described above isused in one of the electric vacuum cleaners of the embodiments that havealready been described and those which will be described later, it ispreferable that the ion generator 231 be disposed near the stream of airproduced when the electric blower 14 is driven, and that the iongenerator 231 be fitted in such a way that the surface thereof on whichthe ion generating element 210 is fitted faces the stream of air.

In this case, as opposed to in the ion generator 23 shown in FIG. 3, theion generating element 210 is exposed, and thus can be fitted in aposition where it easily faces the stream of air. After the fitting,connection terminals 257 and 258 (see FIG. 10) on the outside of thecommon case 253 are connected to an unillustrated external power supplyand to the control circuit of the electric vacuum cleaner, so that theion generator 231 generates ions and discharges them in a form mixedwith the stream of air produced inside and outside the electric vacuumcleaner.

Here, the positive ions mentioned above are cluster ions each having aplurality of water molecules attached around a hydrogen ion (H⁺), andare expressed as H⁺(H₂O)_(m) (where m is a natural number). On the otherhand, the negative ions are cluster ions each having a plurality ofwater molecules attached around an oxygen ion (O₂ ⁻), and are expressedas O₂ ⁻(H₂O)_(n) (where n is a natural number).

After being discharged in a form mixed with the air produced inside andoutside the electric vacuum cleaner, those positive and negative ions,as described earlier, flock together around airborne objects (particles,bacteria) present in the air inside the space into which they have beendischarged, and chemically react with each other to produce, as anactive substance, hydrogen peroxide H₂O₂ or hydroxyl radical —OH. Thus,through an oxidation reaction, the ions deactivate airborne particlesand kill airborne bacteria. As a result, it is possible to purify theair inside the suction air passage running through the electric vacuumcleaner described below and the air present in the living room where theelectric vacuum cleaner is used.

As shown in FIG. 13, the ion generator 231 may be provided with an iondischarge fan 23 a so that ions are discharged by a stream of airproduced as the ion discharge fan 23 a rotates. Specifically, the iongenerator 231 and the ion discharge fan 23 a may be housed in a casing23 b and then, along with an ion generating circuit and a powersupplying means, built into an ion generator 230, which is then fittedto an electric vacuum cleaner.

This makes it easy to additionally incorporate an ozone-separating or-absorbing function into the casing 23 b, and thus makes its manufactureeasy. As a power supplying means, it is possible to use dry cells,rechargeable cells, or the like. This makes it possible to generate anddischarge ions independently.

In this way, incorporating the ion discharge fan 23 a for dischargingions makes it possible to supply ions irrespective of whether theelectric blower 14 is being driven or not. Thus, with the electricvacuum cleaner placed in a place where air needs to be purified, the iongenerator 231 and the ion discharge fan 23 a can be driven to purify theair in that space. Moreover, by disposing the ion generator 231 and theion discharge fan 23 a in the suction air passage by way of which dustis sucked in through the nozzle unit 6 and air is discharged out of thebody 1, it is possible to supply ions more effectively.

FIG. 8 is a diagram showing a fourth embodiment of the invention. Inthis embodiment, the ion generator 231 is disposed on the inside of therear wall of the body 1 so that ions are discharged into the air that isdischarged through the exhaust opening 1 b, and are thus discharged intothe room by that stream of air. Specifically, near the exhaust opening 1b (for example, closely above the exhaust opening 1 b), an ion dischargeport 37 is formed to penetrate the rear wall of the body 1, and the iongenerator 231 is disposed in close contact with the ion discharge port37.

In this construction, when the control panel 4 (see FIG. 1) is sooperated as to start operation, the electric blower 14 and the iongenerating circuit (not illustrated) are energized, so that the electricblower 14 starts to be driven to suck air in through the nozzle unit 6(see FIG. 1) and the ion generating circuit (not illustrated) starts tooperate to apply a high voltage to the electrode of the ion generator.

First, as the electric blower 14 is driven, the air, containing dust,sucked in through the nozzle unit 6 is introduced, through the hosesocket 8, into the body 1. As air is sucked in in this way, inside thebody 1, as shown in FIG. 8, the air sucked into the first suction airpassage 10 is sucked, through the inflow pipe 20, into the dust cup 16of the dust collector 2 while swirling around.

Thus, the stream of air swirls around inside the dust cup 16, with theresult that, by the action of centrifugal force, the dust contained inthe stream of air is separated from the air and is collected inside thedust cup 16. The air having dust removed therefrom and thus purified issucked through the filter 18 b into the exhaust cylinder 18, is thenpassed through the exhaust pipe 19, outflow pipe 21, and second couplingmember 12 into the second suction air passage 13, and is then passedthrough the electric blower 14 and deodorizing filter 15 so as to bedischarged out of the body 1 through the exhaust opening 1 b.

The positive and negative ions generated by the ion generator 231 aredischarged out of the body 1 through the ion discharge port 37 so as tobe mixed with the air near the exhaust opening 1 b. As a result, ionsare carried by the stream of air discharged through the exhaust opening1 b so as to reach all corners of the room, achieving air purificationinside the stream of air and inside the room.

As shown in FIG. 14, the electric blower 14 and the deodorizing filter15 may be disposed at a distance from each other so as to leave a space40 between the discharge side of the electric blower 14 and thedeodorizing filter 15 of the body 1, with the ion generator 231 disposedto point toward the space 40. This permits ions to reach the deodorizingfilter 15, and thus makes it possible to kill bacteria settled on thedeodorizing filter 15.

A fifth embodiment of the invention will be described below withreference to the drawings. FIG. 15 is a diagram showing the fifthembodiment of the invention. In this embodiment, the ion generator 231is disposed on the outside of the rear wall of the body 1, and ions aregenerated toward the stream of air discharged through the exhaustopening 1b so that ions are discharged into the room by that stream ofair.

Specifically, in a rear part of the body 1, a projecting part 39 isformed so as to overhang the exhaust opening 1b, and, below thisprojecting part 39, an ion generation chamber 38 is formed. The iongenerator 231 is deposed inside this ion generation chamber 38. The iongeneration chamber 18 is located closely above the exhaust opening 1 b,and has an ion discharge port 37 located near the exhaust opening 1 b.

In this construction, when the control panel 4 (see FIG. 1) is sooperated as to start operation, the electric blower 14 and the iongenerating circuit (not illustrated) are energized, so that the electricblower 14 starts to be driven to suck air in through the nozzle unit 6(see FIG. 1) and the ion generating circuit (not illustrated) starts tooperate to apply a high voltage to the electrode of the ion generator.

As a result, first, as the electric blower 14 is driven, the air,containing dust, sucked in through the nozzle unit 6 is introduced,through the hose socket 8, into the body 1. As air is sucked in in thisway, inside the body 1, as indicated by broken-line arrows in FIG. 15,the air sucked into the first suction air passage 10 is sucked, throughthe inflow pipe 20, into the dust cup 16 of the dust collector 2 whileswirling around. Thus, the stream of air swirls around inside the dustcup 16, with the result that, by the action of centrifugal force, thedust contained in the stream of air is separated from the air and iscollected inside the dust cup 16. The air having dust removed therefromand thus purified is sucked through the filter 18 b into the exhaustcylinder 18, is then passed through the exhaust pipe 19, outflow pipe21, and second coupling member 12 into the second suction air passage13, and is then passed through the electric blower 14 and deodorizingfilter 15 so as to be discharged out of the body 1 through the exhaustopening 1 b.

The ions generated by the ion generator 231 are discharged out of theion generation chamber 38 through the ion discharge port 37 so as to bemixed with the air near the exhaust opening 1 b. As a result, ions arecarried by the stream of air discharged through the exhaust opening 1 bso as to reach all corners of the room, achieving air purificationinside the stream of air and inside the room.

As shown in FIG. 16, the ion generation chamber 38 may be so disposed asto discharge ions toward the exhaust opening 1 b, with the bottom faceof the ion generation chamber 38 made open to form an exhaust opening41, with the ion generator 231 disposed on the inside of the rear wallthereof, and with an exhaust opening 42 formed near the ion generator231. This permits ions to be discharged toward the air dischargedthrough the exhaust opening 1 b of the body 1, and thus makes itpossible to purify the discharged air in a centralized manner so thations are distributed to all corners of the room through the exhaustopenings 41 and 42 by a stream of clean air.

A sixth embodiment of the invention will be described below. FIG. 17 isa diagram showing the sixth embodiment of the invention. In thisembodiment, ions are mixed with the air that is discharged through theexhaust opening 1 b so as to be discharged into the room by that streamof air. Specifically, the exhaust opening 1 b is fitted with a cover 43so as to form a separate mixing chamber 44 below an ion generationchamber 38 provided in a rear part of the body 1, and an exhaust opening45 is formed in the rear wall of this cover 43. The ion generationchamber 38 is located closely above the exhaust opening 1 b, and has anion discharge port 37 facing the interior of the mixing chamber 44.

In this construction, when the control panel 4 (see FIG. 1) is sooperated as to start operation, the electric blower 14 and the iongenerating circuit (not illustrated) are energized, so that the electricblower 14 starts to be driven to suck air in through the nozzle unit 6(see FIG. 1) and the ion generating circuit (not illustrated) starts tooperate to apply a high voltage to the electrode of the ion generator231. As a result, first, as the electric blower 14 is driven, the air,containing dust, sucked in through the nozzle unit 6 is introduced,through the hose socket 8, into the body 1. As air is sucked in in thisway, inside the body 1, as shown in FIG. 17, the air sucked into thefirst suction air passage 10 is sucked, through the inflow pipe 20, intothe dust cup 16 of the dust collector 2 while swirling around.

Thus, the stream of air swirls around inside the dust cup 16, with theresult that, by the action of centrifugal force, the dust contained inthe stream of air is separated from the air and is collected inside thedust cup 16. The air having dust removed therefrom and thus purified issucked through the filter 18 b into the exhaust cylinder 18, is thenpassed through the exhaust pipe 19, outflow pipe 21, and second couplingmember 12 into the second suction air passage 13, and is then passedthrough the electric blower 14 and deodorizing filter 15 so as to bedischarged through the exhaust opening 1 b into the mixing chamber 44.The air remains in the mixing chamber 44 for a while, and is thendischarged through the exhaust opening 45 into the room.

The ions generated by the ion generator 231 are drawn into the mixingchamber 44 by the stream of air passing therethrough so as to be mixedwith the air inside the mixing chamber 44. As a result, inside themixing chamber 44, the ions are mixed evenly with the air dischargedthrough the exhaust opening 1 b. This makes it possible to purify thedischarged air in a centralized manner so that ions are distributed toall corners of the room through the exhaust opening 45 by a stream ofclean air.

FIG. 18 is an external view of the electric vacuum cleaner of a seventhembodiment of the invention, showing its state during storage. FIG. 19is a sectional view of the body shown in FIG. 18, taken along line A-A.The body 1A of the electric vacuum cleaner of this embodimentincorporates an electric blower 14, is provided with casters 46 on bothsides, has a mixing chamber 44 formed by the casters 46, andincorporates an ion generator 231. The body 1A is freely movable in alldirections. Moreover, a dust collector 2A is disposed between the body1A and a nozzle unit 6. To the nozzle unit 6 is connected a suction pipe301, which is sealed with seals 311 a and 311 b and is slidably providedrelative to the dust collector 2A.

Alternatively, as shown in FIG. 21, the casters 46 may be provided onlyaround the periphery, with caster covers 601 provided inside them so asto form an ion mixing chamber 44. This permits the ion generator 231 tobe maintained easily with only the covers 601 removed.

The stream of air sucked in through the nozzle unit 6 is passed througha hose socket 8, the electric blower 14, a filter 15, and a cord reel 51so as to be discharged through a ventilation openings 46 b formed in thecasters 46. The filter 15 is so arranged as to enclose the electricblower 14. This helps reduce the noise produced by the electric blower14, and makes it possible to adopt a filter with a large area,contributing to good ventilation efficiency.

Thus, it is possible to arrange a HEPA filter with extra fineventilation pores such as to catch dust as small as 1 μm or less. Theouter circumference of the filter 15 may be covered with a soundproofmaterial such as urethane to achieve securer soundproofing. The electricblower 14 is held on the body 1A by way of damping members 503 and 504formed of rubber or the like.

During storage, the electric vacuum cleaner is leaned on stands 501. Asshown in FIG. 18, the stands 501 are provided in pairs; specifically,for each of the casters 46, two stands 501 a and 501 b are provided oneither side of its rolling direction so as to be rotatable aboutrotation shafts 511 a and 511 b, respectively. Moreover, the stands 501a and 501 b are coupled together by couplers 505 (see FIGS. 20A and20B), and are loaded by springs 506 with a force that tends to causethem to pop outside the casters. The body 1A of this type is freelymovable in all directions, and is therefore, during storage, preventedfrom rolling by the stands 501.

FIG. 20A is a side view of the body IA, showing its posture duringcleaning operation. In this state, the stands 501 are kept away from thefloor to permit the casters 46 to roll and thereby permit the body 1A tofreely move. Thus, the stands 501 do not hamper cleaning. When the body1A is rotated in the direction indicated by the arrow, the stands 501 amake contact with the floor, then rotate about the rotation shafts 511a, and thus retract into the body 1A. As the stands 501 a rotate aboutthe rotation shafts 511 a, the stands 501 b, which are coupled theretoby the rods 506, also rotate about the rotation shafts 511 b in theirretracting direction.

When the body 1A is rotated further, as shown in FIG. 20B, all thestands 501 are retracted. When the stands 501 are located right below,all the stands 501 and 501 b are, at their ends, in contact with thefloor. Even when the body 1A is rotated further in the directionindicated by the arrow until the stands 501 a come off the floor, thestands 501 b remain in contact with the floor, and thus none of thestands 501 prop outside the body 1A. This permits smooth rotation of thebody 1A. The stands 501 are fitted, at their ends, with damping members512 formed of a damping material such as rubber or urethane to preventimpact and damage resulting from collision with the floor.

In an upper part of the body 1A, opposite to the stands 501, is provideda handle 502 that permits the electric vacuum cleaner to be carriedaround. As described above, even in the state shown in FIG. 20B, thestands 501 are in contact with the floor, and therefore, for storage,the body 1A needs to be lifted upward so that the ends of the stands 501come off the floor to permit the stands 501 to return to their originalposition under the force exerted by the springs 506. That is, by liftingup the handle 502 to permit the body 1A to come off the floor, it ispossible to return the stands 501 to their original position.

The handle 502 is rotatable about a rotation shaft 502 a. To return thestands 501 to their original position outside the casters 46 forstorage, the handle 502 is rotated to the position indicated by brokenlines in FIG. 30B and is then lifted up. A locking means is provide toprevent the handle 502 from rotating beyond a predetermined position.

A projection 502 b is formed on the handle 502, and a recess 502 c thatengages therewith is formed in the body 1A. Thus, when the handle 502 islifted up, the projection 502 b makes contact with the recess 502 c sothat the handle 502 is held in the position indicated by the brokenlines in FIG. 20B. This prevents instability of the body 1A when it islifted up. Moreover, then, the ends of the stands 501 remainsubstantially parallel to the floor, permitting secure storage on thefloor.

When the handle 502 is let go, it returns, with the help of a spring(not illustrate) or the like, to the position indicated by the solidlines. Here, the electric vacuum cleaner may be so configured as torecognize the storage state to drive the ion generator 231 independentlyfor a predetermined length of time. This permits purification to beperformed automatically for a predetermined length of time inside acomparatively airtight space such as the storage space.

Alternatively, as shown in FIG. 22, the body 1A may be provided with,independently of the control panel 4 for the electric vacuum cleaner, adrive switch 400 for driving the electric blower 14 and the iongenerator 231. With this construction, even in a space other than theaforementioned storage space, for example in a closet, the body 1A canbe placed with the connection hose 7 removed, and the drive switch canbe turned on so that the air inside this space is sucked in anddischarged and meanwhile the generated positive and negative ions aredischarged into the space in order to achieve purification in the space.

In this case, it is preferable that, after the drive switch 400 is sooperated as to turn the power on, the electric blower 14 and the iongenerator 231 be driven for a predetermined length of time (for example,30 minutes). Thus, it is preferable to provide a time control circuit(not illustrated) to permit the setting of the driving time.

The drive switch 400 may be provided directly on the body 1A, or may beprovided in the form of a remote control system for remotely controllingthe body 1A, with a receiver 402 provided on the body 1A and atransmitter 401 provided as a separate unit. With such a remote controlsystem, even when the body 1A is placed in a narrow space as in acloset, the user can drive the electric blower 14 and the ion generator231 by operating the remote control unit. This helps further enhance theusability.

FIGS. 29A and 29B show examples of the control circuit for controllingthe electric blower and the ion generator. FIG. 29A shows an example ofthe control circuit for simultaneously driving the electric blower 14and the ion generator 231 housed in the body 1A described above. On thecontrol panel 4 (see FIG. 22) is provided a switch 41 a that isconnected in series with both the electric blower 14 and the iongenerator 231.

Likewise, as the drive switch 400 (see FIG. 22) is provided a switch 41b that is connected in series with both the electric blower 14 and theion generator 231. Moreover, the remote control system, composed of thetransmitter 401 and the receiver 402 (see FIG. 22), includes a switch 41c that is connected in series with both the electric blower 14 and theion generator 231.

It is preferable that the switches 41 a and 41 b be so structured thattheir contact is closed or opened as a turning-on or -off operation isperformed on the control panel 4 or the drive switch 400. On the otherhand, it is preferable that the switch 42 c be built as an electroniccircuit switch that is controlled according to a signal fed from thereceiver 402 as a turning-on or -off operation is performed on theremote control unit.

Through the operation of the control circuit described above, when thecontrol panel 4, the drive switch 400, or the remote control unit is sooperated as to turn the power on, the corresponding switch 41 a, 41 b,or 41 c is closed. As a result, electric power starts to be suppliedfrom a power supply D to the electric blower 14 and the ion generator231, so that the electric blower 14 and the ion generator 231 start tobe driven.

On the other hand, when the control panel 4, the drive switch 400, orthe remote control unit is so operated as to turn the power off, thecorresponding switch 41 a, 41 b, or 41 c is opened. As a result,electric power stops being supplied from the power supply D to theelectric blower 14 and the ion generator 231, so that the electricblower 14 and the ion generator 231 stop being driven.

Thus, for example, in a case where air is purified while the interior ofthe room is cleaned, or in a case where the air in a space such as acloset is sucked in and discharged so as to be purified, whichever ofthe switches suits the purpose can be operated to drive the electricblower 14 and the ion generator 231.

FIG. 29B shows an example of the control circuit used when, in place ofthe ion generator 231, the ion generator 230 shown in FIG. 13 isprovided in the body 1A. On the control panel 4 are provided a switch 41a that is connected in series with the electric blower 14 and a switch42 a that is connected in series with the ion generator 231 of the iongenerator 230 and with the motor 23 c of the ion discharge fan 23 a.

As the drive switch 400 is provided a switch 41 b that is connected inseries with the ion generator 231 of the ion generator 230 and with themotor 23 c of the ion discharge fan 23 a. Likewise, the remote controlsystem, composed of the transmitter 401 and the receiver 402 (see FIG.22), includes a switch 41 c that is connected in series with the iongenerator 231 of the ion generator 230 and with the motor 23 c of theion discharge fan 23 a.

It is preferable that the switches 41 a and 42 a be so structured thattheir contact is closed or opened as a turning-on or -off operation isperformed on the control panel 4. In this case, in response to aturning-on or -off operation performed on the control panel 4, theswitches 41 a and 42 a may be closed or opened simultaneously.

Alternatively, the switches 41 a and 42 a may be so controlled that, inresponse to a turning-on operation performed on the control panel 4, theswitch 42 a is closed first and then the switch 41 a is closed and, inresponse to a turning-off operation performed on the control panel 4,the switch 41 a is opened first and then the switch 42 a is opened.Alternatively, an unillustrated timer control circuit may be providedthat so controls that, when a turning-off operation is performed on thecontrol panel 4, the switch 41 a is opened first and then, apredetermined length of time thereafter, the switch 42 a is opened.

The control panel 4 may be so configured that the switches 41 a and 42 acan be operated individually. With the configuration described above,flexible control is possible, for example, by first stopping the drivingof the electric blower 14 and then, with a delay, stopping the drivingof the ion generator. This makes it possible to further purify the airfloating around after being discharged by the electric blower 14.

It is preferable that the switch 41 b be so structured that its contactis closed or opened as a turning-on or off operation is performed on thedrive switch 400. The switch 41 b may be so structured that, whenclosed, it is opened a predetermined length of time thereafter by anunillustrated time control circuit. It is preferable that the switch 41c be built as an electronic circuit switch that is controlled accordingto a signal fed from the receiver 402 as a turning-on or -off operationis performed on the remote control unit. The switch 41 c may be sostructured that, when closed, it is opened a predetermined length oftime thereafter by an unillustrated time control circuit.

When the control panel 4 is so operated that the switches 41 a and 42 aare closed simultaneously, electric power starts to be supplied from thepower supply D to the electric blower 14, to the ion generator 231 ofthe ion generator 230, and to the motor 23 c of the ion discharge fan 23a, so that these start to be driven. When the drive switch 400 or theremote control unit is so operated that the corresponding switch 41 b or41 c is closed, electric power start to be supplied to the ion generator231 of the ion generator 230 and to the motor 23 c of the ion dischargefan 23 a, so that these start to be driven.

Accordingly, for the purpose of cleaning a room and purifying air, thecontrol panel 4 can be operated so that the electric blower and the iongenerator 230 are driven simultaneously. On the other hand, since theion generator 230 is so configured as to be able to discharge ions onits own, for the purpose of discharging ions into a room withoutcleaning it, the drive switch 400 or the remote control unit can beoperated so that the ion generator 230 alone is driven.

In this construction, when the control panel is so operated as to startoperation, the electric blower 14 and the ion generating circuit (notillustrated) are energized, so that the electric blower 14 starts to bedriven to suck air in through the nozzle unit 6 (see FIG. 1) and the iongenerating circuit (not illustrated) starts to operate to apply a highvoltage to the electrode of the ion generator 231.

As a result, first, as the electric blower 14 is driven, the air,containing dust, sucked in through the nozzle unit 6 is introduced,through the suction pipe 301, into a dust cup 16 while swirling around.Thus, the stream of air swirls around inside the dust cup 16, with theresult that, by the action of centrifugal force, the dust contained inthe stream of air is separated from the air and is collected inside thedust cup 16.

The air having dust removed therefrom and thus purified is passedthrough the hose socket 8 into the body 1A, and is then introduced,through the electric blower 14, deodorizing filter 15, and ventilationopening 48 a, into a cord housing 50, where the air cools the cord reel51. This air is discharged through the exhaust opening 1 b into themixing chamber 44, where the air remains for a while. The air is thendischarged out of the body 1 through the exhaust opening 46 b. In thecord housing 50 and the mixing chamber 44 may be arranged, other thanthe cord reel 51, any component, such as a circuit (not illustrated),that generates heat. This permits such a heat-generating component to becooled with the stream of air.

The ions generated by the ion generator 231 are discharged into themixing chamber 44 so as to be mixed with the air inside it. As a result,inside the mixing chamber 44, the ions are mixed evenly with the airdischarged through the exhaust opening 1 b. This makes it possible topurify the discharged air in a centralized manner so that ions aredistributed to all corners of the room through the exhaust opening 45 bya stream of clean air.

Furthermore, in this embodiment, the mixing chamber 44 can be formedinside the casters 46 pivoted on the side walls of the body 1. Thispermits the use of existing components without changing the design ofconventional electric vacuum cleaners. This helps keep the productprices low.

The descriptions given thus far deal only with constructions including acyclone-type dust collecting device and an ion generator. It is,however, also possible to obtain similar effects, as will be describedbelow, with the type of electric vacuum cleaner that collects dust bypassing air through (i.e., by filtering it with) a dust collection bag2A formed of cloth or paper. An eighth embodiment of the invention willbe described below with reference to the drawings. FIG. 23 is an overallperspective view of the electric vacuum cleaner of the eighth embodimentof the invention. As shown in FIG. 23, the electric vacuum cleaner has abody 1, casters 46, a hose 7, a handle 5, and a nozzle unit 6.

FIG. 24 is a sectional view of the body of the electric vacuum cleaner.The body 1 shown in FIG. 24 is provided with a first suction passage10A, an electric blower 14 that drives a motor 54 to rotate a fan 55 andthereby produces a suction stream of air, and a dust collection bag 2Athat collects dust that has been sucked in. The electric blower 14 isfixed inside the body 1 by the use of a support member 56 having acircular opening formed at the center. Moreover, an ion generator 23(231) that generates ions is disposed in the first suction passage 10A,which runs from a hose socket 8 to the dust collector 2A.

When a carpet or the like is cleaned with the electric vacuum cleanerhaving its body 1 constructed as described above, dust, such as animalhair, house mites, mold, and pollen, is sucked in and is collected inthe dust collection bag 2A. When the air containing such dust passesthrough the first suction passage 10A, by the action of the positive andnegative ions discharged from the ion generator 23, the odor-producingsubstances and allergenic chemical substances contained in the air aredecomposed. As a result, the exhaust air discharged out of the electricvacuum cleaner returns to the room as air that is free from not onlydust but also odor-producing substances.

FIG. 25 is a sectional view of the body of the electric vacuum cleanerof a ninth embodiment of the invention. The body shown in FIG. 25incorporates a first suction passage 10A, an electric blower 14 thatdrives a motor 54 to rotate a fan 55 and thereby produces a suctionstream of air, and a dust collection bag 2A that collects dust that hasbeen sucked in. Moreover, an ion generator 23 is disposed between thedust collection bag 2A and an exhaust opening 1 b.

When a carpet or the like is cleaned with the electric vacuum cleanerhaving its body 1 constructed as described above, dust, such as animalhair, house mites, mold, and pollen, is sucked in and collected in thedust collection bag 2A, and the chemical substances such asodor-producing substances contained in the air having dust removedtherefrom are decomposed by the action of the positive and negative ionsdischarged from the ion generator 23. Furthermore, ions are dischargedinto the room by the stream of exhausted air so as to eliminate chemicalsubstances remaining in the room.

FIG. 26 shows the result of measurements of the concentrations of ionsgenerated by the electric vacuum cleaner shown in FIG. 25. Theconcentrations of ions were measured with an ion counter manufactured byDan Kagaku Co., Ltd., Japan, with the ion sensor portion thereof placedat a distance of 10 cm from the exhaust opening.

As shown in FIG. 26, it was found that, the faster the wind speed of theexhaust air discharged along with ions through the exhaust opening 1 b,the higher the ion concentrations, and thus the larger the quantities ofions discharged.

Next, it was evaluated how effective the ions discharged from theelectric vacuum cleaner were on odor-producing substances. As anodor-producing substance, ammonia was fed into a box of acrylic resinhaving a volume of 1 m³ in such a way that the initial concentration ofammonia was 10 ppm. Then, the electric vacuum cleaner shown in FIG. 24was placed inside the box, and the box was then sealed so as to beair-tight. Then, ions were discharged through the exhaust opening at anappropriate wind speed, and, 30 minutes later, the reduced amount ofammonia was measured. Then, on the basis of the initial concentrationand the reduced amount of ammonia, the elimination rate was calculatedas 100×(reduced amount)/(initial concentration). FIG. 27 shows theresult.

As shown in FIG. 27, it was found that, the faster the wind speed, andthus the larger the quantities of ions discharged, the more ammonia waseliminated. It was also found that an ammonia elimination rate of about50% was achieved when the wind speed of the ion wind blown out throughthe exhaust opening was 50cm/s.

On the basis of these facts, it was found that, to satisfactorilyeliminate odor-producing substances, the wind speed from the exhaustopening needed to be at least 50 cm/s, which resulted in ionconcentrations of about 10,000 ions/cm³.

The electric vacuum cleaner of this embodiment can be realized verysimply by externally adding a single device for air purification. Thisconstruction can be applied not only to electric vacuum cleaners of thetype described above as an example but also to electric vacuum cleanersadopting any other dust collection method.

It is to be understood that the embodiments described above are merelyexamples of constructions according to the present invention. That is,the present invention can be implemented in any other manners thanspecifically described above, and many modifications and variations arepossible within the scope of the subject matter of the presentinvention. For example, one of the first, second, third, and eighthembodiments may be combined with one of the fourth, fifth, sixth,seventh, and ninth embodiments.

Specifically, the suction air passage by way of which air is sucked inand discharged may be divided into an upstream part and a downstreampart with respect to the electric blower, with an ion generator providedin each of the upstream and downstream parts thereof This permits notonly the interior of the electric vacuum cleaner to be purified, butalso permits ions to be mixed with the air discharged out of theelectric vacuum cleaner so that purification is performed both insideand outside the electric vacuum cleaner.

The configurations shown in FIGS. 8 to 14, 24, and 25 can be realizedvery simply by externally adding a device for air purification. Theconfigurations shown in FIGS. 15 to 17, where the ion generator isarranged on the outside, permit easy addition of a separately built iongenerator to an existing electric vacuum cleaner.

As shown in FIG. 13, a blower 23 a may be additionally provided todischarge ions through the ion discharge port of the ion generator 231.This permits ions to be supplied irrespective of whether the electricblower 14 is being driven or not. Thus, with the electric vacuum cleanerplaced in a space, such as a closet, where purification is needed, theion generator 231 and the blower 231 a can be driven to obtain asterilizing, healing, or other effect that suits the intended purpose.

The ion generator 231 shown in FIGS. 18 to 21 or the ion generator 230shown in FIG. 13 may be provided in a device of the type that is movedaround inside a room as it is used by the user or that has the functionof moving around on its own. This makes it possible, as achieved with anelectric vacuum cleaner according to the invention, to performsterilization inside a room to which such a device is carried. Examplesof such devices include, to name a few, hair dryers, telephone handsets,intelligent robots, and self-moving cleaners provided with wheels.

Similar effects can be obtained even in a electric vacuum cleaner of theso-called exhaust-recycling type wherein the exhaust is recycled, i.e.,the stream of air sucked in is returned from the exhaust side of theelectric blower 14 to the nozzle unit 6. FIG. 28 is a sectional view ofthe body 1B of an exhaust-recycling type electric vacuum cleaner. To thehose socket 8 are connected a first suction air passage 10 thatcommunicates with the dust collecting device and a return stream tube 10b that communicates with the downstream side of the electric blower 14.

Correspondingly, though not illustrated, through a connection pipe and aconnection hose are formed a suction air passage 7 a and a return streampassage 7 b that communicate with the first suction air passage 10 andthe return stream pipe 10 b, respectively. The connection hose isremovably fitted into the hose socket 8. Thus, the suction air passage 7a and the return stream passage 7 b communicate with the interior of anunillustrated nozzle unit through the connection hose and the connectionpipe.

The stream of air sucked in through the nozzle unit 6 is then sucked,through the suction air passage 7 a, first suction air passage 10, dustcollection device 2, and second suction air passage 13, into theelectric blower 14, and is then recycled by being returned through thedeodorizing filter 15, return stream pipe 10 b, and return streampassage 7 b to the interior of the nozzle unit 6. In this construction,by discharging ions from the ion generator 23 into the suction airpassage by way of which air is sucked in through the nozzle unit 6 andfed to the electric blower 14, or into the return stream passage by wayof which air is recycled by being returned from the electric blower 14to the nozzle unit 6, it is possible to purify the suction stream of airor the recycled return stream of air.

Industrial Applicability

As described above, according to the present invention, by dischargingboth negative and positive ions, or negative ions alone, generated by anion generator, and by discharging those ions into the air sucked in orinto the air discharged out of an electric vacuum cleaner as an electricblower is driven, it is possible to eliminate unpleasant odors producedwhen the electric vacuum cleaner is used and to kill bacteria such asmicroorganisms all over a wide area.

In particular, in a case where the ion generator is disposed near anexhaust opening, it is possible to discharge ions into a room. Thismakes it possible to deliver ions to all corners of the room and purifythe air inside the room. Moreover, by driving the ion generator alongwith a blowing means for blowing ions, it is possible to purify the airin the room even while the electric vacuum cleaner is stored.

Moreover, the ion generator uses a needle-shaped electrode. This permitsan electric field to concentrate, and thus permits discharge to takeplace more easily, resulting in efficient discharge of ions into thesucked air. In addition, this needle-shaped electrode is arranged alongthe stream of air. This makes the electrode almost free from dustelectrostatically settling thereon, and thus makes its maintenance easy.

Moreover, the present invention can be applied to electric vacuumcleaners adopting any dust collection method, such as those employing acyclone-type dust collecting device or a dust collection bag. Thus,simply by adding an ion generator as a device for air purification, itis possible to purify air that tends to be polluted during cleaning.

1. An electric vacuum cleaner that, while driving an electric blower,sucks in air containing dust, then passes the airthrough a suction airpassage, and then discharges the air out of the electric vacuum cleaner,comprising: an ion generator for generating H⁺(H₂O)_(n) as positive ionsand O₂ ⁻(H₂O)_(m) as negative ions, wherein airborne germs present inair are killed by the positive and negative ions.
 2. The electric vacuumcleaner according to claim 1, wherein ions generated by the iongenerator are fed into the suction air passage.
 3. (Canceled)
 4. Theelectric vacuum cleaner according to claim 2, wherein the ion generatoris disposed away from a heat source inside a body of the electric vacuumcleaner.
 5. An electric vacuum cleaner that, while driving an electricblower, sucks in air and then discharges the air out of the electricvacuum cleaner, comprising: an ion generator for generating H⁺(H₂O)_(n)as positive ions and O₂ ⁻(H₂O)_(m) as negative ions, wherein the air isdischarged out of the electric vacuum cleaner after being mixed with thepositive and negative ions so that airborne germs present in air arekilled by the positive and negative ions.
 6. The electric vacuum cleaneraccording to claim 5, wherein the air sucked into the electric vacuumcleaner is discharged out of the electric vacuum cleaner after beingpassed through a purification filter, and the air is mixed with the ionsafter being passed through the purification filter. 7-12. (Canceled) 13.The device according to claim 6, wherein, when air is fed to an iongenerating part of the ion generator at a rate of 50 cm/s or more,concentrations of the positive and negative ions are each 10,000ions/cm³ or more at a position 10 cm away from the ion generating part.14. An electric vacuum cleaner that has casters arranged on both sidefaces of a body having an electric blower housed therein and thatexhausts the electric blower of air through ventilation openings formedin the casters, comprising: an ion generator that generates H⁺(H₂O)_(n)as positive ions and O₂ ⁻(H₂O)_(m) as negative ions into a mixingchamber formed by the casters wherein airborne germs present in air arekilled by the positive and negative ions generated by the ion generator.15. An electric vacuum cleaner that has an electric blower and an iongenerator housed in a body, the body comprising: a drive switch fordriving the ion generator, the drive switch being provided independentlyof a control panel for controlling the electric vacuum cleaner, whereinairborne germs present in air are killed by the ion generator.
 16. Theelectric vacuum cleaner according to claim 15, further comprising: timermeans for driving the electric blower and the ion generator for apredetermined length of time after the drive switch is operated.
 17. Theelectric vacuum cleaner according to claim 1, wherein quantities of ionsgenerated by the ion generator is controlled according to a power withwhich the electric blower is driven.
 18. The electric vacuum cleaneraccording to claim 1, wherein the ion generator is driven for apredetermined length of time according to a storage state of theelectric vacuum cleaner.
 19. The electric vacuum cleaner according toclaim 1, wherein the ion generator has two ion generating electrodes sothat the positive and negative ions are generated from the two separateelectrodes.
 20. The electric vacuum cleaner according to claim 1,wherein the ion generator can variably control a proportion betweenquantities of positive and negative ions generated.